A quantum dot (QD), which is also called a nanocrystal, is a nanoparticle composed of elements of Groups II and VI or elements of Groups III and V. Because electrons and holes are subject to quantum confinement, a continuous energy band structure becomes a discrete energy level structure with molecular characteristics. After being excited the quantum dot can emit fluorescence, and the luminescence spectrum can be controlled by changing the size of the quantum dot. With good fluorescence intensity and stability, quantum dots are good electroluminescent materials.
At present, quantum dots have been widely used in the display field as display materials. For example, by using quantum dots as light-emitting materials in a light-emitting layer, a quantum dot light-emitting diode has been manufactured.
The inventors have found that at least the following problems exist in the prior art: because quantum dots are not small molecular organic materials, there is currently no quantum dot patterning method suitable for mass production.
At the same time, patterning cannot be conducted by means of evaporation and ink jetting. At present, a generally accepted method in the industry is a transfer printing method, which is yet immature, involves great technical difficulty, and currently cannot be used for mass production. In addition, there are quite few suppliers for transfer printing equipment, which restricts the development of QLED.